1. Field of Invention
The present invention relates to a procedure for fastening an object in a holding device, as defined in the preamble of claim 1, and to a hydraulic holding device as defined in the preamble of claim 4.
2. Description of Related Art
Several types of hydraulic holding devices are used to fasten tools, work pieces and various shafts. However, prior-art solutions have the drawbacks that they require a large space and are structurally unbalanced, preventing the use of high rotational speeds. Previously known are also small-sized holding devices that make use of the thermal expansion of metals. The drawbacks of these devices are a narrow tolerance range, difficult fastening and releasing procedures and a reduced accuracy due to multiple fastening and releasing operations, which always require heating and cooling. Another drawback with many prior-art holding devices is that their holding force is insufficient to hold objects having notches in them. A notch may be e.g. a segment removed from a cylindrical shaft over part of its length. A further drawback with prior-art holding devices is that their restraint moment varies with the temperature.